I need to design an op-amp circuit that has the following input/output relationship: Vout = ln(Vin) and I am told to use a logathrimic op amp with values NVT = 47.6mV, Is = 3.035 x 10^-9 A, and R = 1k ohm
The logathrimic op amps Vout is equal to -NVT*ln(Vi) + NVT*ln(R*Is)
So, in a nut shell, I need to get -NVT*ln(Vi) + NVT*ln(R*Is) down to ln(Vi) with only 3 op amps.
I'm not asking for a step by step on this, but I've been at this thing for hours and I just wanna know where I am going wrong.
So far my design consits of 2 logathrimic op amps and one inverter, but I'm not sure how to get my values to knock out the NVT.
Any help would be great.
Thanks
The logathrimic op amps Vout is equal to -NVT*ln(Vi) + NVT*ln(R*Is)
So, in a nut shell, I need to get -NVT*ln(Vi) + NVT*ln(R*Is) down to ln(Vi) with only 3 op amps.
I'm not asking for a step by step on this, but I've been at this thing for hours and I just wanna know where I am going wrong.
So far my design consits of 2 logathrimic op amps and one inverter, but I'm not sure how to get my values to knock out the NVT.
Any help would be great.
Thanks